Electric-hammer switch.



A. WENDELBURG.

ELECTRIC HAMMER SWIT' AIfPLICATlON FILED APR 28. I915. RENEWID SEPT. 20.1911.

1,250,402 Patented Dec. 18, 1917.

. UNITED STATES PATENT OFFICE.

ALEX WENDELBURG, OF NEW YORK, N. Y., ASSIGNOR 'I'O PITTSBURGH ELECTRICTOOL COMPANY, OF NEW YORK, N. Y.. A CORPORATION OF PENNSYLVANIA.

BDECTRIC-HAMMER SWITCH Specification of Letters Patent.

Patented Dec. 18, 191 7.

Original application filed July 28, 1914. Serial No. 853,784. Dividedand this application filed. April 28, 1915,

Serial No. 24,547.

i To all whom it may concern 'able others skilled in the art to which itappertains to make and useazhe same.

Tl11S invention relates to electric hammers adapted for use in chipping,calking, rivet- -ing, cutting and other work requiring a.

rapid succession of blows upon a. suitable tool. proved form of electrichammer which'is simple fn construction, which may be manufactored at lowcost, which is soconstructed as to permit of cooling by immersion in aliquid, which is of comparatively light weight and which possesses suchstrength and rigidity. as will enable it to withstand the continualjarring to which it is subjected in uscl'.

The invention herein claimed involves the provision bf an improved formof c rcuitcontrolling mechanism whereby the operation of the hammer isgoverned. This involves the provision of a cavity in the handle of thehammer in which a circuit-brmiln-r of Special form is removably mounted,this circuit-breaker being operable to open and close the circuit to thecoils of the hammer. The construction of the circuiflbreaker is such asto insure a. good ctlntact when the opemtin handle of the switch ismovedto the close position and to minimize the clan ger of arcing at theterminals by the pro "ision of auxiliary contact surface which' effect adelayed breaking of the circuit.

The invention also involves numerous other features of improvement inthe construction of the hammer whereby great strength, good wearingqualities and ample protection of the parts are obtained. These andother features of the invention will be better understood by referenceto the folowing description taken in connection with the accompanyingdrawing which shows the prefegred embodiment of the invention li ereiuclaimed;

.' In the drawing, Figure l is a central sec- Renewed September 20,1917.

The intention is directed to an ini-"" Serial No. 192,413.

tional view of a hammer embodying my invention;

Fig. 2 is an enlarged sectional view. through the circuit-controllingmechanism;

Fig. 3 is a transverse section of the circuitcontroller on line 33 ofFig. 2; and

Fig. i is a diagram of the circuit connection.

Referring to these drawings, the frame of the hammer consists primarilyof a tubula casting l and a handle casting 5. The cast. mg -l is ofnonmagnetic material, preferi ably phosphor bronze, and the tubularpassage therethrough contains a reciprocating solenoid core or plunger6, ada ited to strike the end ofa. tool to be. inserte through thehollow tool-guide 1- l,herein'aftr mentioned. The casting l is proigidedwith radially disposed walls 7, '8 and-,9, which provide spaces betweenthem for'solenoid coils 10 and 11. These coils are -wound in oppositedirections and serve to'develop magnetic fields which actuate theplunger 6 constitutin the core of the soleiioid. The'coils are inc ose-dby. a casing 12 which is preferably a piece of steel tubing. This tubingand the walls 7, 8 and 9. are of'such dimensions that the tubing fitssnugly around the walls, and the spaces between the walls, 7, 8 and 9,and the casi 12 are completely filled by the coils 10 51% 11. Theforward-ends of-the casting 4 and the casing 12 are connected togetherby a nozzle 1". For this purpose, the projecting 0nd of the casting 4 isprovided with an ex terior thread with which the nozzle l3 coacts andthe nozzle is formed with a projecting flange adapted to fit tightlyover the end of the casing 12, as shown. The forward end of the hammeris provided with a tool-guide 14 of slightly smaller internal diameter,so that the plunger cannot slip out. This toolguide is preferably formedto fit into the end of the casting 4' and have threaded engagement withthe end of the nozzle 13. By this construction, the forward ends of thecasting and the-casing 12 are rigidly connected by the nozzle 13 so asto preclude relative moveu'ient of these parts, and the nozzle effectssuch a tight fit with the guide and cos- 'ing as will preclude theentrance of a liquid central passageway through the casting 4 isprovided with an enlargement for a cushioning spring 16 to receive theblow of an impact block 15. A portion ofthis block lies within thetubular passage through the casting 4 in which the strikiu g plunger 6reciprocates.- The remainder of the block 15 is of larger diameter andlies Within the en largement of the tubular passage. The coiled spring16 bears at one end upon the block 15, the latter being provided with aperipheral flange 17 encircling the end of the spring so as to hold thelatter against lateral movement. Between the larger portion of the blockloand the Wall at the end of the enlarged'chamber is a washer 18 of toolsteel which receives the blow of the block 15 when the latter isreturned by the spring 16. The opposite end of the enlarged chamher isclosed by a cap 19 which has threaded engagement with the wall of thecasting 4. The exteriorly threaded flange on this cap serves as aretainer coactin with the end of spring 16 to hold the latter inposition. This flange and the similar flange 17 on block 15 prevent sidemotion of the spring so that chafing of the spring upon the walls of itsinclming chamber and consequent lack of uniformity in the action of thespring are prevented. Y

The casting for the handle 5 has a central opening therethrough in whichthe rear ends of the casting 4 and the casing 12 are received. Forsecuring these parts together, the casing 12 may conveniently have asleeve 2-0 secured thereon by means of rivets and forming acircumferential flange. The end 21 of the handle casting 5 closelyincloses the end of the casing 12 and is exteriorly threaded to coactwith a ring or collar on which is a lip 23 adapted to engage the flange20. lVhen the sleeve 22 is screwed up tightly, the end 21 of the handlecasting and the lip 23,'both of which closely inclose the casing 12,engage the "flange 20 on opposite sidcsthereof and grip thehandle'casting 5 to the casing 12. The casting 5 is also interiorlythreaded to coact with a threaded plug 24 which fits closely around theadjacent end of the casting 4,

- its end abutting against a flange 25 thereon.

In this way, both the casing 12 and the casting a are connected to thehandle casting 5 and these connections are such tight ones that they notonly afi'ord the necessary degree of strength, but also precludethe pas-;'sage of water through them.

The plug 24 is pro ided with a hole through the centertherem as are alsothe caps 19 and 15. Because of this Provision,

' air may pas freely from the space between the block 15 and thestriking plunger 6 as radial slot from end to end as is shown forcircuit-controller with his thumb. The parts of thiscircuit-controllerare located within a tube of insulating material andmay all be assembled within this tube before the latter is inserted inits cavity within the handle casting. Also, the parts of thiscircuit-controller are especially constructed so as to provide for ahard rubbing engagement of the contacting surfaces and a delayed breakof the circuit zit-auxiliary contacts. The

construction cf'the circuit-controlling apparatus is shown more clearlyin Fig. 2. In the bottom of the cavity in the handle casting 5 are awasher 26 and block 27 of insulating material both of which areremovably held. in place by a screw 50, as shown in dotted lines in Fig.2. In the insulating block 27 are two'contacts 28, which have wiresconnected thereto which passthrough a passage 29 formed in the casting 5and are connectedto terminals upon a l of insulating material'whichis'secured upon ock 30 the castingli'n the space between the. latter Iand the end-of the casing 12, The contacts 28 are adapted to be en agedby the, endsof pins 31 located in a cy 'ndrical block 32 of insulat i'ngmaterial which is secured in the end or'. tube 33 of insulating materialof a size adapted to fit snugly within the cav-- ity formed in thecasting 5, v This block 32 is secured to the tube 33 by one or more pins34. The-opposite'ends of the pins 31 are threaded into contacts 35 whichare of semi circular form. and are secured upon the block 32 directlyopposite each other. The

ends of these contacts'35jrising from the block 32 are spaced apart. andon their ads acent sides theyLare provided with inclined curveddepressions as shown at 36. (Fig; 3). Z

- second block 37 ofins'ulating material is secured in position'w'ithin'the tube 33 and forms-a guide for a; movable cont-act carrier 38. Thiscarrier has the contact 39 secured thereon, this contact being in theform ofv a cup or bell theskirt of,whic h is slotted so a as to form apluralitybfr resilient contact fingers. The contact-carrir'38 has acavity formed therein -which'- receives a spring 42 bearing upon awasher of heat-insulating material resting onthe enlarged end 43 of a'short rod 44 carrying an auxiliary contact 1-5. This auxiliary contactis of conical form as shown. The rod 44 is adapted to 'slide in theopening provided for its recepmay also any water which enters thissp'ace.- The plungerfi is preferably provided with a tion in the contactcarrier 38. The spring, 42, being inclosed in a chamber whose walls areof heat-insulatingmaterial, is correspondingly protected against loss oftemper due to the heat of sparking at the contacts when the current isbroken; a spring -11 is interposed between the black 37 and :rflange ofthe stem 53 of insulating material hav ing at its top a press buttonto.When the parts of the circuit-controller have been assembled within thetube 33 of insulating material, the latter is moved into the cavity inthe handle 5 and the end of that cavity is inclosed by a threaded cap47. t

The! wires for carrying current to and from' the hammer enter thestructure through a passage 48 provided in the handle casting 5. Aconnection block 49 of in sulating material carrying three terminalsinsulated from each other-is preferably prowhich block the wires leadingto the hammer are connected.

The wiring for carrying current to and from the hammer is illustrated'diagrammatically in Fig. 4. By reference'to' Fig. 4, it will be notedthat two of the wires or conductors pass from terminals on theinsulating block 49 to the block of insulating material 30, and, fromsaid block 30 are con tinned by other wires until they are connectedrespectively to the non-adjacent ends of the coils 1" and 11. Theadjacent ends of these coils are connected together, and, from theirpoint of connection, a wire leads to the block 30, and is continued byanother wire from the block 30 to one of the contacts 28. From the othercontact 28, a. wire leads to the third terminal upon the insulatingblock 49. These nnections are such that the connection from the junctionof the two coils '10 and 11 to the other side of the circuit may beopened or closed by the circuit-breaking mechanism located in the cavityof the handle, since this connection is made through the contacts 35which are connected or disconnected by the bell 39 and auxiliary contact45. In Fig. 4, the insulating-"block 30 is shown as provided with.

indii'idual grooves for the reception of the several wires or-co:doctors referred to. In assembling and disassembling the hammer, thewires leading from the insulating block 419 and from one of the contacts28 to the insulating block 30 can be electrically connected with thecontinuations of those 'wires respectively by means of suitableconnecting and disconnecting screws 56, as will be readily understood. yI

When the button lti'is pressed, the contact 39 and auxiliary contactare: moved .forward are; the latter engages the inclined'sun faces 36upon the contacts 35, so closing the circuit. continued, the auxiliarycontact 45 is moved him relative .to the contact carrier 38 therebycompressing the spring 42. As this takes place, the contact 39 moves 0\er the contacts by the arts Asthe movement of button 46 is 35 so as toeffect an electrical connection between them. -By reason of theresiliency of the slit-ted skirt of the bell-shaped contact sp ing 41forces the contact carrier 38 and the contact 39 upwardly so as tointerrupt the connection of the contacts 35 by the contact 39. Whilethis is taking place, however, the auxiliary contact 45 does not im-.mediatelv disengage the contacts 35 for the riderl upon the (lasting 5,at this point, to reason that it is still kept in contact with themmomentarily by the spring 42. After the contact 39 has moved away,however, a distance sufiiclent to clear contacts 35, the

contact 45 disengages these contacts so as to break the circuit. As a;consequence, whatever arcing there is takes place between the contact 45and the surfaces 36, and has no effect upon the surfaces of contactbetween the-slit bell 39 and the outer peripheries of" the contacts 35,which therefore remain'constantly bright and "in efiicient conductivecondition.

The circuit-breaker herein described may be readily constructed at lowcost by assenb' bling the parts within. the insulating tube 33 andthereafter inserting that tube in the cavity in the handle of thehammer; In OFGIMJQII, this circuit-controller serves to c ose and o nthe circuit effectively", a good contact of arge Surface area t of thecontact 39120 inclose thetwo contacts 35- and the contact 45m spiteadthecontacts 35 into hard en- .ga ment; with the contact 39 mg insured twill be noted that the'construction of the hammer is such as will permitof coolmg it by the whole ofthe forward portion of theihamme'r in acooling li uid.

Elie coils 10 "and 11 are so inclosed'an the connections between theinclosing parts are such that the entrance of the'cooling 1i uid intothe chambers for the. ,coils'is preclu ed.

To further insure this result, the flange 57 is brazed to the: shell orcasing 12, and a thin asbestos gasket 58 'is'inserted at the pointindicated; in addition 'towhich the screw-threads connecting the nozzle'13 to the end of the 'castin 4 and to the toolsguide 14 may be shellackbefore assembling the.-

parts, thereby making absolutely water-tight f joints. Furthennorthe'parts of the hammer are connected together with such strength andrigidity that the continual and severe jar- -ring incident 'to theuseofth'e hammer will not cause the parts to, work loose. The tool steelwasher 18 which.receiyes the return blow of the block is fixed inposition within its cavity. preferably by shrinking it in place, inorder that it may not follow the upward movement of said block.

--I claim:

1. In an electric h nnner, the combination of a pair of yieldingcontacts, a plunger, a slotted bell carried by said plunger and movableto embrace and bridge said contacts, and means for spreading saidcontacts against the inner face of said hell.

2. In an electric hammer, the combination of a pair of yieldingcontacts, a springpressed plunger, a metal bell carried by said plungerand movable therewith to embrace and bridge said yielding contacts, anda wedge-shaped conductor adapted to enter between and spread saidyielding contacts,

substantially. as described.

3. In an electric :hammer, the combination of a pair of yieldingcontacts, a-springpressed plunger, a slotted metal bell carried by saidplunger and movable to envelop and bridge said yielding contacts, and anauxiliary contact member yieldingly mounted on said plunger and adaptedto enter between and bridge said yielding contacts.

a. In an electric hammer, the combination of a pair of yielding contactmembers, a sliding spring-pressed plunger, a. conductive element carriedbysaid plunger and adapted to engage the outer faces of said contactmembers and form a bridge between said members, and a spring-pressed rodmounted in said plunger and adapted to enter between said contactmembers and spread the same against the inner face of said element, saidrod being slidingly mounted and pro-. jecting from said plunger farenough to give a delayed break when said plunger moves its conductiveelement out of engagement with said contact members.

5, In a hammer handle, adigitally. operated plunger, a bridgingbonductorearned by said plunger, a. pair {if contacts to be bridgedthereby, a springpressed rod slidingly mounted in said plim 'ger, saidro'dhaving an auxiliary tapering contact adapted to enter between saidfirst named contacts before their engagement with the bridging bridgedcontacts when said plunger is withconductor, said auxiliary-contactgiving a delayed break for current between said drawn. y

An electric hammer handle having a cavity, a pair of contacts locatedtherein, a,

member movable in said cavity and carrying a conductor adapted toinclose and yieldingly. embrace said pair of contacts, an auxiliarycontact mem er slidingly mounted in said movable member and adapted toenter between said pair of contacts and electricall y connect the samewhen said member moves inward, and a. spring permitting rela contacts insaid tu tire movement of said auxiliary contact member to delay theinterruption of the circuit between said first-named pair of contactswhen said movable member moves outward, substantially as described.

7. In an electric hammer, a handle having a cavity therein, a tube ofinsulating material in said cavity, a pair of contacts located in saidtube, a movable member having a contact of circular form located thereonadapted to engage and connect said contacts, and a movablespringactuated contact upon said movable member-adapted to enter betweensaid contacts and spread the same, substantially as described.

8. In an electric hammer, a. handle having a cavity therein, pair ofcontacts fixed at the base of mid cavity, a tube of insulating materialremovably mounted in said cavity, a pair of' contacts located in saidtube, and adapted to be detachably connected with said first-mentionedpair of contacts, a digitally operated member movable in said tube andcarrying a contact adapted to inclose and yielding] embrace said pair ofbe, an auxiliary contact member slidably mounted in said movable memberand adapted to enter between said air of contacts in said tube when saidmemr moves inward, and a spring permitting relative movement of saidauxiliary contact member to delay the interruption of the circuit whensaid movable member moves outward; substantiallyas described.

9. In an electric hammer, a handle having a cavity therein, a'tube ofinsulating material in said cavity, a pair of yielding contacts locatedin said tube, a digitally operated plunger movable in said tube andcarrying a slotted bell adapted to inclose and yieldingly embrace saidpair of contacts, said plunger beingprovided with a' chamber, a springin saidchamber, and an auxiliar contact member engaged by said spring anslidingly mounted in. said plunger, said auxiliary contact member beingadapted to enter between said pair of contacts'and spread the. sameagainst the inner faceof the bell when the plunger moves inward andgiving a delayed break for current between the pair of contacts whensaid plunger moves outward. I i

10. In an electric-hammer, a handlehaving a cavity therein, a pair ofcontacts located in said cavity, each of said contacts being ofsemi-circular outline, a digitally operated plunger movable in saidcavity and carrying a. slotted bell adapted to inclose eing providedwith a chamber therebetween when the plunger moves mward and before saidbell reaches said contacts, the spring within said plunger permittingrelative movement between said auxiliary contact and said-slotted bell,and giving a delayed break for current between said pair of contactswhen said plunger moves outward in said cavity.

11. In an electric hammer, a handle hav-. a tube of insulating ing acavity therein,

material in said cavit ,a pair of contacts located in said tube, amovable member having a contact located thereon adapted to en age andconnect said contacts "and a movabfia spring-actuated contact upon saidmovlocated in said tube, a mova mg a 'contact located thereonfladapted,to

able member adapted to enter between said 1 contacts.

12. In anelectric hammer, a handle having a cavity therein a tube ofinsulating material-in said cavity, a 1Emir of contacts le'member hav-20,

engage and connect said contacts and a movable spring-actuated contactupon said movable member adapted to enter between said contacts andspread the same. 25

In testimony whereof I aflix

